2. Trees can prevent wind and fix sand, keep water and soil, and absorb all kinds of dust. An acre of forest can absorb 20-60 tons of dust a year.
3. Woods can reduce noise pollution. A 40-meter-wide forest belt can reduce noise10-15db. Noise pollution has caused great harm to human life, study, work and rest, and can be said to be people's "enemy". Therefore, we should pay more attention to afforestation. Noise can also lead to hearing loss, deafness and stupidity, as well as heart, blood pressure and nerve abnormalities in long-term life. Even, it can make people die under long-term noise. In this way, the forest can reduce the noise by four or five times.
The secretions of trees can kill bacteria. There are 34,000 bacteria per cubic meter of air in the open space, and only 300-400 bacteria in the forest.
Planting trees is the obligation of every citizen, and the state has designated March 12 as Arbor Day. Planting trees is of great benefit to our study, work and life.
5. Trees can lower the temperature and increase the humidity. At 30 degrees, the temperature can be reduced to about 20 degrees.